Spear points for spear guns have conventionally been formed with a shaft machined from stainless steel. Because substantial machining is required for the conventional spear point, the material used for the shaft from which the spear point is formed is typically 300 stainless steel, which is a relatively soft material having a hardness of about 15 Rockwell.
The spear points used for sport fishing have a pointed head having a reduced diameter shank portion. A sleeve is rotatably mounted over the reduced diameter shank portion and apertures are provided on opposite sides of the sleeve in which pins are mounted to pivotally attach a pair of folding wings. The wings fold against the shaft and are provided with a resilient spring and a sleeve retainer is slidably mounted on the point, adjacent the rear of the head. The retainer is slid along the shaft to overlie the folded ends of the wings and retain them in their folded positions, against the bias of a resilient spring.
The aforementioned construction requires considerable machining. It is necessary to manufacture the spear point in at least two parts, requiring machining of a threaded attachment between the two parts. It is also necessary to machine one or both mating ends of the two head portions to reduced diameters to receive the aforementioned sleeve which supports the folding wings. The rear portion of the head is also machined with necessary attachment means, typically with an internally threaded bore or externally threaded shank to attach the head to the main shaft of the spear. The aforementioned machining precludes the use of very hard machine steel such as steels having hardness values greater than about 30 Rockwell, e.g. stainless steel grade 17-4 which has a hardness of 44 Rockwell.
The use of very hard machine steel for the heads of spear points is desired since the softer steels currently in use do not stand up under the abuse typically experienced with the spear heads. The spear heads often hit rocks, breaking or bending their points, and thus requiring frequent replacement and repair. While the use of very hard machine steels for this service would greatly reduce or eliminate the frequency of maintenance heretofore required and extend the service life of the spear heads, no one heretofore has employed such steels because of the extensive machining required with the conventional spear head design.